Almost every student, at least one who ever follows chemistry subject, knows what a chemical compound is. To say in the simplest and most common definition, a compound, chemically speaking of course, is that of a chemical substance, and a pure one that is, which has two, or could be more of, different chemical elements. These elements, which are bonded together to make the chemical compound, can always be further separated into much simpler substances by the means of the proper chemical reaction, or reactions. Thus, any chemical compound must have quite a unique and fixed chemical structure. That is to say, the compound must have the exact ratio of atoms and every one of which will be held in place by such spatially defined arrangement of chemical bonds. Take water, for example (and as also the easiest example of a chemical compound being around plentifully in this planet). In the light of chemistry, this liquid material is seen to have been built by two different kinds of elements: two of hydrogen atoms and one of oxygen atom which are held together in such specific relation called the bond.
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| Chemical Compound model hydrogen bonds in water |
The chemical bonds, however, are of different types. One chemical compound can be called having a molecular bond which is covalent in the form. The prefix co- means that of joint or associated, while valence means the number of bonds (usually the electrons) one specific atom can form with the other atoms. Of this valence, chemistry knows a chemical compound which could have those atoms that are univalent or monovalent, thus only able to form only one covalent bond, or those of divalent atoms which could form either two sigma-bonds to two completely different atoms or one sigma-bond and one phi-bond to one single atom. Another type of bond which could make a chemical compound is that of the ionic bond. This specific bond is made when two opposite charged ions form an electrostatic attraction to each other. To be ionic, the bond is usually made of a metal, or a cation in chemical term, and a nonmetal element called the anion. The important thing about this chemical knot is that there is no chemical compound which can be made of pure ionic bonding. That is to say, all ionic bonding has, to same degree, covalent bonding. Hence, this bond is to be understood as that of a bonding in which the ionic character is simply greater than its covalent character.
The next bond which could make a chemical compound is that of the metallic one. When two different metallic phenomena occur and combine together, metallic bonding rises: delocalization of electrons and the deficiency of electrons. Of course, there are many metallic physical properties which are to be accounted for the bond. These include the thermal property, malleability, luster, ductility, strength, opacity and eletrical conductivity. The last type of bond which could make a chemical compound is the complex or dipolar bonding. Known also as coordinate or dative covalent bonding, the structure resembles that of 2-center, 2-electron in covalent bonding type where the two of those electrons are coming from the same atom. The very term of dipolar bonding is much more common in organic chemistry to name a chemical compound such as amine oxides where the basic amine element becomes the donor of two electrons to one oxygen atom. The very last thing needed to say about this chemical compound is that it is to be differentiated from those of pure chemical elements even if these pure elements do have molecules consisting of multiple atoms of single element. For the latter, chemistry uses diatomic or polyatomic molecules instead of chemical compound.
